1. Field of the Invention
The present general inventive concept relates to an audio reproduction system, and more particularly, to a method and apparatus to automatically control audio volume that suddenly changes between channels or scenes.
2. Description of the Related Art
Currently, due to a rapid development of communication and broadcasting technologies and combining of communication and broadcasting fields, a service for conveniently watching digital broadcasting while moving is provided.
In general, audio and video (AV) reproduction devices such as digital televisions (DTVs) or home theaters allow viewers to watch TV or video of a personal video recorder (PVR) by connecting to various external devices and selecting various types of signals and broadcast channels for watching terrestrial analog broadcasting, satellite broadcasting, and cable broadcasting.
In conventional DTVs or home theaters, when a user changes a channel or a scene is changed, an audio volume level suddenly changes and thus the user feels uncomfortable.
For example, a user individually changes channels of DTVs to identify a condition of a screen. The DTVs automatically and sequentially search for broadcast channels of received frequency bands.
However, while changing channels, a user feels that volume levels of each broadcast channel are slightly different which occurs due to a receive sensitivity of each broadcast channel. Accordingly, such a volume change due to changing channels should be corrected.
Thus, in conventional AV reproduction devices, a method of controlling audio volume using a linear curve is used to correct a volume change occurring due to the changing of channels or scenes.
FIGS. 1A and 1B are graphs illustrating a relationship between magnitudes of input audio signals and output audio signals used in the conventional method of controlling audio volume.
Referring to FIG. 1A, the conventional method of controlling audio volume defines a volume controlling section as three sections such as a boost section 110, a no modification section 120, and a cut section 130.
For example, when a volume of the audio signal is above an optimum level (cut section 130), a gain of the audio signal decreases. When the volume of the audio signal is at an optimum level (no modification section 120), the gain of the audio signal is maintained. When the volume of the audio signal is below an optimum level (boost section 110), the gain of the audio signal increases.
However, as illustrated in FIG. 1B, the volume cannot be controlled in a center portion 150 of the no modification section 120 and sound deterioration occurs due to discontinuous control in a first boundary portion 140 of the boost section 110 and the no modification section 120 and a second boundary portion 160 of the cut section 130 and the no modification section 120.